The present invention relates to a laser microscope adaptor apparatus with focusing capability over a large continuous range. The invention is particularly useful in surgical laser microscope apparatus for delivering a laser beam to an object, such as a tissue to be cut, removed, or coagulated and is therefore described below with respect to such application.
Surgical lasers are often used in microsurgery, such as ENT, neurosurgery or gynecology, wherein a working laser beam (e.g., from a CO.sub.2 laser), and a visible aiming beam (e.g., from a HeNe laser), are directed to the surgical site through a microscope adaptor, commonly termed a laser micromanipulator which includes a joystick by which the surgeon can direct the laser beam over selected locations in the field of view.
Surgical microscopes can be used at fixed working distances or a range of variable distances depending on the sophistication of the microscope. In general each clinical application has its own particular working distance. For example, for vocal cord treatments, a working distance of 400 mm is normally used; whereas for neurosurgery, a working distance of 300 mm is normally used. Working distances are set either discretely by changing the objective lens on the microscope or continuously in newer microscope models. To focus the laser beam at the focal plane of the microscope, laser focusing mirrors in the micromanipulator are moved in accordance with the working distance set on the microscope.